class_docstr: Computes LR as minimum of 1/beta and 1/(gamma * step) at each step.
  
  This is a required step for privacy guarantees.
code: def __init__(self):
      self.is_init = False
      self.beta = None
      self.gamma = None
  
imports: import tensorflow.compat.v1
  from tensorflow.compat.v1.python.keras.optimizer_v2 import optimizer_v2
  from tensorflow.compat.v1.python.ops import math_ops
  from tensorflow_privacy.privacy.bolt_on.losses import StrongConvexMixin
label_desc: Use image node_id 1 to create a new GammaBetaDecreasingStep object from inherited base classes: optimizer_v2.learning_rate_schedule with example: obj = GammaBetaDecreasingStep()